Hi Cheng, I'm not sure I understand your question, but here's what little I know about the preempt function.
runtime.asyncPreempt is used to implement asynchronous preemption. Basically, the go runtime scheduler occasionally suspends the execution of a goroutine to check if it has been running too long. If it has, it "preempts" the routine and passes control to another goroutine. This prevents long running goroutines from stealing all the resources from other routines. The following information is probably considered "dangerous" because it depends on low level knowledge that is probably going to change in the future.. There is a function in the runtime package called GOMAXPROCS which gives you some control over the number of system threads used by the go scheduler. You might be able to get a tiny bit of control over how often the preempt function is called by changing this value. There's also a LockOSThread function which you can call to lock the routine to a thread and prevent the current goroutine from being preempted (the OS may still preempt the thread). It's counterpart, UnlockOSThread unlocks the routine from the thread so that it can again be used by the scheduler to run different goroutines. On Tuesday, March 14, 2023 at 8:18:34 PM UTC-6 cheng dong wrote: > here is the go env > > ` > GO111MODULE="on" > GOARCH="amd64" > GOBIN="" > GOCACHE="/home/dongcheng/.cache/go-build" > GOENV="/home/dongcheng/.config/go/env" > GOEXE="" > GOEXPERIMENT="" > GOFLAGS="" > GOHOSTARCH="amd64" > GOHOSTOS="linux" > GOINSECURE="" > GONOPROXY="" > GONOSUMDB="" > GOOS="linux" > GOPRIVATE="" > GOPROXY="https://goproxy.cn,direct"; > GOROOT="/usr/local/go1.18" > GOSUMDB="sum.golang.org" > GOTMPDIR="" > GOTOOLDIR="/usr/local/go1.18/pkg/tool/linux_amd64" > GOVCS="" > GOVERSION="go1.18.1" > GCCGO="gccgo" > GOAMD64="v1" > AR="ar" > CC="gcc" > CXX="g++" > CGO_ENABLED="1" > GOWORK="" > CGO_CFLAGS="-g -O2" > CGO_CPPFLAGS="" > CGO_CXXFLAGS="-g -O2" > CGO_FFLAGS="-g -O2" > CGO_LDFLAGS="-g -O2" > PKG_CONFIG="pkg-config" > GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 > -fdebug-prefix-map=/tmp/go-build3091739208=/tmp/go-build > -gno-record-gcc-switches" > ` > > attachment is the profile data > On Wednesday, March 15, 2023 at 10:11:40 AM UTC+8 cheng dong wrote: > >> my code run some logic every second in a Tick function, sometimes i could >> be very slow(like 5x time), i profile the process and found most of time is >> doing runtime.asyncPreempt. however in "source view", these asyncPreempt >> disappeared. >> >> [image: profile315.jpg] >> > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/96317d77-d01d-48c8-9a2a-8af472750396n%40googlegroups.com.
